Conventionally, a tank includes an orifice in its bottom portion, i.e. its portion closest to the ground, that is closed by a fitted plate that is referred to as a “fuel plate” if the tank is a fuel tank.
The fitted plate comprises a plate proper having an opening that is covered by a member known in the art as a “canister”.
It should be observed that below and for convenience, in order to comply with the terminology used in the art, the term “plate” is used to designate the plate as such and the term “fitted plate” is used to designate the plate together with its accessories including the above-mentioned canister.
The canister comprises an outer casing that opens to a feed pipe, e.g. providing the connection between the tank and an engine, with a base of the canister being fastened to the plate. The base then possesses at least one through orifice for allowing the liquid contained in the tank to flow towards the feed pipe.
In addition, the fitted plate includes a pump fastened thereto, the pump passing through the opening in the plate in order to project into the inside of the casing. The pump then serves to cause the liquid to flow out from the tank through the canister. It should be observed that on a fitted plate of a fuel tank, the pump is usually referred to as a “booster” pump.
In order to avoid liquid escaping from the tank through the opening in the plate when the operator removes the pump, the canister includes a movable member, such as a resiliently sliding cylindrical member or a valve, for example, suitable for closing each of the through orifices when the pump is absent.
When the operator inserts the pump, the pump actuates the movable member, which slides inside the outer casing to open each through orifice. Conversely, when the operator removes the pump, the movable member returns to its original position, e.g. under drive from a spring, and closes each through orifice.
In addition, the fitted plate generally includes a quick drain cock for draining the tank quickly, or indeed regulation bleed means at its low point. The quick drain cock is permanently fitted to the plate.
Thus, the device provided for draining the tank comprises a cock that is arranged in permanent manner on a plate. More precisely, the device comprises a fitted plate comprising at least: a canister; a pump; and a quick drain cock.
It can thus be understood that the quick drain cock increases the weight of the fitted plate even though it is used only occasionally. Nevertheless, in the context of an aircraft fuel tank, maintenance operations are made easier by the presence of quick drain means. Merely eliminating such quick drain means as they stand does not appear to be possible.